Sprayers for liquids, particularly, those of the hand-operated trigger type, ordinarily include a check valve in a chamber located just inside the sprayer outlet which serves to block off the inlet passage to the chamber from the interior of the sprayer until the liquid becomes pressurized and to block the passage of liquid from the chamber except to allow it to pass through certain swirl or other passages to the outlet. For instance, U.S. Pat. No. 3,685,739 to Vanier shows a shuttle valve which is free to move in a sprayer outlet chamber wherein upon operation of the sprayer a partial vacuum downstream of the chamber causes it to block the entrance of air through the outlet orifice into the pumping means of the sprayer by closing the liquid supply passage after which the shuttle moves in the opposite direction as the pressure of the fluid in the supply passage builds up and blocks the outlet except for the swirl passages.
Another U.S. Pat. No. 3,061,202 to Tyler shows a check valve which achieves the same general purpose as that of Vanier but is spring-loaded so that it remains on its seat to close the liquid supply passage at all times except when the sprayer is operated to create a sufficient pressure in the supply passage to overcome the spring and thus force the valve to open. Flow of the fluid to be sprayed then occurs, in each instance, to a swirl chamber from which it is sprayed through an outlet orifice. The inlet passage 35 of Tyler is closed by a conical poppet 29 in his showing but flat poppets have been used for this purpose as well. The present invention is an improvement in this art and is distinct from it in that the swirl chamber closure plate, the spring and the poppet are all made of one-piece as a unitary, molded construction thus eliminating the need for three separate parts as shown by Tyler and yet still achieving the same desirable flow and shut-off characteristics. Elimination of the plurality of parts means less assembly time and thus less cost of manufacture, improved simplicity, one-piece reliability and the elimination of compatibility of material problems and problems associated with metal parts such as corrosion for instance.
Another U.S. Pat. No. 3,620,421 to MacGuire-Cooper shows a valve requiring lateral movement of the valve to tilt it on its seat to open the outlet to the flow of a product from its container below the valve. A resilient annular portion is provided which acts to restore the valve to its closed position and this annular portion is molded integrally with the valve portion. In the present invention, on the other hand, the valve is linear in its action and includes an integrally molded sinuous spring which compresses only upon the application of proper operating pressure supplied by the pump action of the sprayer, and, the sinuous spring is carefully designed and molded to operate only when the pressure is sufficient to produce a spray.